Mold for chilled rolls.



WITNESSES WWW Patented Mar. 8, 1910.

2 SHEETS-SHEET l.

P. E. MESTA.

MOLD FOR CHILLED ROLLS.

APPLICATION FILED JAN. 16, 1908.

951,769. Patented Mar. 8, 1910.

2 SHEETS-SHEET 2. Y

WITNESSES INJENTOR UNITED STATES PATE ornrcs.

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SYLVAN IA.

A CORPORATION OF PENN- To all whom it may concern:

Be it known that I, FREDERICK E. MESTA, of West Homestead, in the countyof Allegheny and State of Pennsylvania, have invented a new and usefulImprovement in Molds for Chilled Rolls, of which the following is afull, clear, and exact description, reference being had to theaccompanying drawings, forming part of this specification,

in which- Figure 1 is a central vertical section of a mold constructedin accordance with my invention; and Fi 2 is a side elevation of thesame, partly bro en away.

y invention relates to the manufacture of chilled rolls and similararticles of circular cross section, and is designed to provide animproved mold therefor.

Heretofore in the common method of milk ing chilled rolls, the chillmold has always been made of cast iron, and the walls, or the thicknessof the shell, has usually been made from one-fourth to one-third thediameter of the hole that is, if the chill mold would be twenty-fourinches inside diameter, the thickness of the wall would be from six toeight inches. This heavy wall, in the common practice of making chills,was not necessary to hold the strain of the hot n'ietal but was madeheavy in order to absorb the heat of the liquid iron when poured in themold, thus forming the chill. With this heavy wall, the total expansionof the mold is small, and also very slow; therefore, the metal in themold would commence to contract while the heavy walls of the mold arestill expanding, thus leaving a space between the mold and the roll soonafter the metal is poured, which retards the chilling and also veryoften makes uneven chills.

My invention is designed to increase the depth of chill obtained with acertain grade of iron, thus enabling me to obtain the same depth ofchill with a lower grade of chilling iron having a lower carbon, andconsequently greater toughness and tensile strength and less expansionand contraction. It is also designed to give an even and uniform chill.

In carrying out my process, I employ a comparatively thin metal mold orchill, and I positively extract the heat from the molten I metal byapplying a cooling medium to the Specification of Letters Patent.Application filed January 16, 1908. Serial No.

.but also keep Patented Mar. 8, 191% 411,082.

outer surface 'of' the chill. Moreover, by using a thin chill, theexpansion will take place almost immediately after the pouring of themetal, so that the outer shell of the chilled roll will not be formeduntil the chill mold has expanded to substantially its entlre amount. Bya plying a positive cooling medium to the t in chill'mold durmg thesetting of the metal, I not on y extract the heat from the molten metal,thus being-able to get the depth of chill required, contra-ctmg thethinchill so that it is always in perfect contact with the roll until thechill is formed, and by this means always makes the chill' even.

In the drawings, in which I show one form of apparatus for carrying outmy inventlon, 2'represents the chill mold roper, which consists of ametal cylinder liirished comparatively smooth, inside by machining, andwhich is preferably thin, relatively to the chill' molds now employed.The chill mold may be made of cast iron, cast steel, wrought steel, orother suitable metal, and should beadapted to conduct differenttemperatures therethrough rapidly. This chill or ring is preferably heldin a vertical position by circular top and bottom plates 3 and l, havingcentral holes provided with flanges 5 and 6, which fiti-ntocorresponding recesses in the ends of the chill In-old thus formingsli joints which hold the: mold vertically w ileallowing it to freelyexpand and contract. Through these'plates extend bolts 7,, which arepreferably provided with integral collars 8, serving to space apart theplates and secure the cope. These bolts are made of the roper length andare preferably held by Eeys 9.

The cope l0 and drag 11 may be held in position by suitable dowel pins13, engagin the cope and drag flanges and the top an bottom mold plates.Around the chill mold, I wind in helical form a flexible metal pipe 14,this being preferably made in a series of overlying 0011s of which Ihave shown three, though any desired number of coils may be used. Thiselastic spring coil is employed for the circulation of-a cooling medium,such as water, brine, or ammonia gas.

In carrying out the rocess, the cope and drag having been mo ded in sandin the usual manner and the parts having been HOMESTEAD, PENNSYLVANIA,ASSJ IG'NOB, TO MESTA MACHINE COMPANY, OF PITTSBURG, PENNSYLVANIA,

assembled, as shown in the drawings and held by suitable clamps, asshown at 15, the metal is poured in, in the ordinarymanner. Immediatelyafter pouring, the cooling medium is circulated through the circulatingcoils of tubing, preferably entering the innermost coil first and beingtaken away from the other end of the outer coil, thus positivelyextracting heat from the chill mold or forcing a cooler temperaturethereinto. The forcing of a cooler temperature should begin at least asearly as when thechill mold has expanded after the metal is poured in,and as this moment can not be determined exactly, I prefer to start theflow of fluid immediately after ouring. The circulation of the coolingflui is preferably maintained until the chill mold has contracted to itsnormal diameter. At this time, I preferably shut off the flow of coolingmedium and the metal then begins to heat up slowly while the chilled rolis contracting away from it to the slight amount which is necessary inorder to draw the roll. This gradual heating up action of the chill moldacts to anneal the chill and impart strength to the roll. The roll maythen be taken out in the ordinary manner. If desired, the mold may beartificially heated before pouring, in order to insure the desiredexpansion of the mold.

The advantages of my invention will be apparent to those skilled in theart. Owing to the positive extraction of heat by applying a coolinmedium to the thin conducting chlll ring, can greatly increase the depthof chill with iron havin a given amount of carbon, and can keep the moldin contact with the roll during the chilling action. Consequently, I canobtain the desired depth of chill with a less percentage of carbon inthe iron, and hence, can use a better grade of iron which will roduce atougher roll having greater tensi e strength. The coiled pipe acts toexpand and contract under the action of the chill mold to accommodateitself to the difierent diameters thereof, while at the same time,continuously extracting heat therefrom, owing to the circulation of thecoolin medium. Whereas in an ordinary chill, tl ie chilling efiect ofthe mold is constantly decreasing as it heats up, I avoid this in mymold and force the chill into the iron of the roll through any desiredperiod, irrespective of the amount of heat conducted to the chill.mold.

An even uniform chill is insured by my simple method which enables avery simple apparatus to be used. The comparatively thin chilling ringor mold shrinks as fast or faster than the metal of the roll, and thusfollows up the roll and maintains contact with it under the ressure ofthe shrinkage caused by the coolmgicoils. The chill is so proportionedas to t ickness, that when it is cooled to its normal size, the rollwill have sufiicient further contraction to release it from the mold,and preferably so that it expands to substantially the same amount asthe metal of the roll contracts. There is no complication due to the useof wings or separated segments on chill rings, and a much better articleis produced y reason of the actual and forcible extraction of heat.

Owing to the very rapid chillingl and setting of the metalcircumferentially, t e feed from the sink head into the body of the rollis more complete and the roll is less liable to have blow-holes andspongy portions in the neck and wabbler.

The invention is equally ap licable to chilled car wheels or to thechilling of any other articles of circular cross section.

The mold may be made in one piece, as shown, or in two or moretransversely divided sections and is preferably made of cast or rolledsteel, or other material having a greater coeflicient of expansion andcontraction than cast iron.

The cooling medium may be applied to its exterior in different manners,though I prefer, the one shown, and many other variations may be madewithout departing from my invention.

I claim: I

1. A chill mold for casting articles of chilled iron, having surroundingseparated fluid conduits and in exterior contact with the chill andmeans for circulating a cooling medium through said separated conduits,substantial] as described.

2. A chill mold for casting chilled iron articles, having an elasticsystem of separated channels surroundin and exterior thereto, andarranged to allow free expansion and contraction of the chill, and meansfor circulating a cooling medium through the se arated channels,substantially as describe 3. A chill mold for casting chilled ironarticles, having separated exposed channels surrounding the exterior ofthe mold, thus providing separated bodies of water or cooling fluid, andmeans for circulating a cooling fluid through said channels,substantially as described.

4. A chill mold for casting chilled iron articles, having surroundingexposed channels formed of pipe in contact with the chill, and means forcirculatin a cooling medium through said pipes, su stantially asdescribe 5. A chill mold for casting chilled iron articles, having asurrounding pi e coil in contact therew th, said ipe coil eing externaland exposed, su stantially as described.

6. A chill mold for casting chilled rolls of greater length thandiameter, said mold consisting of steel having a greater coeficient ofexpansion and contraction, and a higher melting point, than cast iron,substantially as described.

7. A chill mold for casting chilled rolls, of greater length thandiameter, said mold consisting of steel having a greater coeflicient ofexpansion and contraction, and a higher melting point than cast iron,and external cooling conduits surrounding said steel chill mold,substantially as described.

8. A chill mold of a proper length for casting chilled rolls, andconsisting of steel having a greater coelficient of expansion andcontraction than cast iron, and also having a higher melting point, andseparated exposed fluid channels surrounding and in contact with thechill, substantially as described.

9. A solid chill mold having end-holdin means arranged to allow freeexpansion an contraction, said chill having external exposed separatedchannels surrounding it for the circulation of a cooling medium,substantially as described.

In testimony whereof, I have hereunto set my hand.

F. E. MESTA. Witnesses:

J. O. HORNING, H. F. WAHL.

